Breathe in that smoke and your lungs begin to produce more mucus – thicker mucus. They can’t handle the excess, so the mucus sits there, more likely to get infected, and making you cough. Smoking, and the carbon monoxide that comes with it, can damage the lung tissue, reducing the amount of oxygen you can breathe in and making less oxygen available to the rest of your body. Long-term, it can lead to chronic lung diseases such as COPD.

The chemicals from smoking damage your blood cells, too – and that all-important muscle that pumps them, your heart. It puts you at increased risk of plaque build-up in your arteries, and therefore at greater risk of heart disease, heart attacks and strokes.

Since smoking affects these two critical systems, there is no part of your body that’s unaffected by smoking cigarettes.

That’s the bad news. The good news is some of the negative effects of smoking are reversed within minutes of quitting. Check out this list from the American Cancer Society:

• 20 minutes after quitting: Your heart rate and blood pressure drop
• A few days after quitting: The carbon monoxide level in your blood drops to normal.
• 2 weeks-3 months after quitting: Your circulation improves and your lung function increases
• 1-12 months after quitting: Coughing and shortness of breath decrease. Your lungs start to clear out that excess mucus and your risk of infection goes down.
• 1-2 years after quitting: Your risk of heart attach drops dramatically.
• 5-10 years after quitting: Your risk of cancers of the mouth, throat and voice box is cut in half. Your risk of stroke decreases.
• 10 years after quitting: Your risk of lung cancer is about half that of a person still smoking and your risk of cancer of the bladder, esophagus and kidneys decreases.
• 15 years after quitting: Your risk of coronary heart disease is close to that of a non-smoker.